Eurasia covers around 55,000,000 square kilometres (21,000,000 sq mi), or around 36.2% of the Earth's total land area. The landmass contains around 5.0 billion people, equating to approximately 70% of the human population. Humans first settled in Eurasia between 60,000 and 125,000 years ago. Some major islands, including Great Britain, Iceland, and Ireland, and those of Japan, the Philippines and Indonesia, are often included under the popular definition of Eurasia, in spite of being separate from the massive landmass.

Physiographically, Eurasia is a single continent.[4] The concepts of Europe and Asia as distinct continents date back to antiquity and their borders are geologically arbitrary. In ancient times the Black Sea and the Sea of Marmara, along with their associated straits, were seen as separating the continents, but today the Ural and Caucasus ranges are more seen as the main delimiters between the two. Eurasia is connected to Africa at the Suez Canal, and Eurasia is sometimes combined with Africa to make the largest contiguous landmass on Earth called Afro-Eurasia.[8] Due to the vast landmass and differences in latitude, Eurasia exhibits all types of climate under the Köppen classification, including the harshest types of hot and cold temperatures, high and low precipitation and various types of ecosystems.

Originally, “Eurasia” is a geographical notion: in this sense, it is simply the biggest continent; the combined landmass of Europe and Asia. However, geopolitically, the word has several different meanings, reflecting the specific geopolitical interests of each nation.[9] “Eurasia” is one of the most important geopolitical concepts; as Zbigniew Brzezinski observed:

“... how America "manages" Eurasia is critical. A power that dominates “Eurasia” would control two of the world’s three most advanced and economically productive regions. A mere glance at the map also suggests that control “Eurasia” would almost automatically entail Africa’s subordination, rendering the Western Hemisphere and Oceania geopolitically peripheral to the world’s central continent. About 75 per cent of the world’s people live in “Eurasia”, and most of the world’s physical wealth is there as well, both in its enterprises and underneath its soil. “Eurasia” accounts for about three-fourths of the world’s known energy resources.”[10]

The Russian concept of “Eurasia” corresponded initially more or less to the land area of Imperial Russia in 1914, including parts of Eastern Europe.[11] One of Russia's main geopolitical interests lies in ever closer integration with those countries that it considers part of “Eurasia.”[12] This concept is further integrated with communist eschatology by author Alexander Dugin as the guiding principle of "self-sufficiency of a large space" during expansion.[13]

^Lewis, Martin W.; Wigen, Kären (1997), The myth of continents: a critique of metageography, University of California Press, pp. 31–32, ISBN0-520-20743-2 "While a few professionals may regard Europe as a mere peninsula of Asia (or Eurasia), most geographers—and almost all nongeographers—continue to treat it not only as a full-fledged continent, but as the archetypal continent."